#!/usr/bin/env pmpython
#
# Copyright (C) 2014-2016,2020 Red Hat.
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.
#
# pylint: disable=bad-whitespace,protected-access,redefined-outer-name
# pylint: disable=too-many-nested-blocks,too-many-boolean-expressions
""" Display tape I/O statistics """

import re
import sys
import signal
from pcp import pmapi, pmcc
from cpmapi import PM_CONTEXT_ARCHIVE, PM_MODE_FORW

# use default SIGPIPE handler to avoid broken pipe exceptions
signal.signal(signal.SIGPIPE, signal.SIG_DFL)

# Tape: r/s w/s kB_read/s kB_wrtn/s %Rd %Wr %Oa Rs/s Ot/s
# These are the metrics tapestat (sysstat) shows and we will do the same
# for starters


#       [root@nkshirsa sysstat]# ls /sys/class/scsi_tape/st0/stats/ -l
#       total 0
#       in_flight
#       io_ns
#       other_cnt
#       read_byte_cnt
#       read_cnt
#       read_ns
#       resid_cnt
#       write_byte_cnt
#       write_cnt
#       write_ns


TAPESTAT_METRICS = [ 'tape.dev.in_flight', 'tape.dev.io_ns',
                     'tape.dev.other_cnt', 'tape.dev.read_byte_cnt',
                     'tape.dev.read_cnt', 'tape.dev.read_ns',
                     'tape.dev.resid_cnt', 'tape.dev.write_byte_cnt',
                     'tape.dev.write_cnt', 'tape.dev.write_ns']


def aggregate(method, aggr_value, value):
    if method == 'sum':
        aggr_value += value
    elif method == 'avg':
        aggr_value += value
    elif method == 'min':
        aggr_value = min(aggr_value, value)
    elif method == 'max':
        aggr_value = max(aggr_value, value)
    else:
        raise pmapi.pmUsageErr
    return aggr_value

class TapestatReport(pmcc.MetricGroupPrinter):
    Hcount = 0
    def timeStampDelta(self, group):
        s = group.timestamp.tv_sec - group.prevTimestamp.tv_sec
        n = group.timestamp.tv_nsec - group.prevTimestamp.tv_nsec
        # n may be negative here, calculation is still correct.
        return s + n / 1000000000.0
    def instlist(self, group, name):
        return dict(map(lambda x: (x[1], x[2]), group[name].netValues)).keys()

    def curVals(self, group, name):
        return dict(map(lambda x: (x[1], x[2]), group[name].netValues))

    def prevVals(self, group, name):
        return dict(map(lambda x: (x[1], x[2]), group[name].netPrevValues))
    def report(self, manager):
        regex = TapestatOptions.Rflag
        if regex == '':
            regex = '.*'

        aggr = TapestatOptions.Gflag
        if aggr and aggr not in ('sum', 'avg', 'min', 'max'):
            print("Error, -G aggregation method must be one of 'sum', 'avg', 'min' or 'max'")
            raise pmapi.pmUsageErr

        precision = TapestatOptions.Pflag
        if precision < 0 or precision > 10 :
            print("Precision value must be between 0 and 10")
            raise pmapi.pmUsageErr

        subtree = 'tape.dev'
        group = manager["tapestat"]

        if group[subtree + '.read_cnt'].netPrevValues is None:
            # need two fetches to report rate converted counter metrics
            #print "found none, returning"
            return
        instlist = self.instlist(group, subtree + '.read_cnt')
        dt = self.timeStampDelta(group)
        timestamp = group.contextCache.pmCtime(int(group.timestamp)).rstrip()

        c_r = self.curVals(group, subtree + '.read_cnt')
        p_r = self.prevVals(group, subtree + '.read_cnt')

        c_w = self.curVals(group, subtree + '.write_cnt')
        p_w = self.prevVals(group, subtree + '.write_cnt')

        c_rkb = self.curVals(group, subtree + '.read_byte_cnt')
        p_rkb = self.prevVals(group, subtree + '.read_byte_cnt')
        c_wkb = self.curVals(group, subtree + '.write_byte_cnt')
        p_wkb = self.prevVals(group, subtree + '.write_byte_cnt')

        # calculate the percentage waits
        c_rpw = self.curVals(group, subtree + '.read_ns')
        p_rpw = self.prevVals(group, subtree + '.read_ns')
        c_wpw = self.curVals(group, subtree + '.write_ns')
        p_wpw = self.prevVals(group, subtree + '.write_ns')
        c_opw =  self.curVals(group, subtree + '.io_ns')
        p_opw = self.prevVals(group, subtree + '.io_ns')

        p_resid = self.prevVals(group, subtree + '.resid_cnt')
        c_resid = self.curVals(group, subtree + '.resid_cnt')
        p_other = self.prevVals(group, subtree + '.other_cnt')
        c_other = self.curVals(group, subtree + '.other_cnt')

        if precision == 1:
            utilspace=precision+5
            awaitspace=precision+6
            rrqmspace=precision+5
            wrqmspace=precision+5
            headfmtavgspace=precision+7
            headfmtquspace=precision+7
        elif precision == 0:
            utilspace=precision+5
            awaitspace=precision+7
            rrqmspace=precision+6
            wrqmspace=precision+6
            headfmtavgspace=precision+8
            headfmtquspace=precision+8
        else:
            utilspace=precision+5
            awaitspace=precision+5
            rrqmspace=precision+5
            wrqmspace=precision+5
            headfmtavgspace=precision+6
            headfmtquspace=precision+6

        tmpspace = precision+5
        if precision == 0 :
            tmpspace = tmpspace  +1

        if "h" not in TapestatOptions.xflag:
            self.Hcount += 1
            if self.Hcount == 24:
                self.Hcount = 1

        if "t" in TapestatOptions.xflag:
            valfmt = "%-24s %-12s %*.*f %*.*f %*d %*d %*.*f %*.*f %*.*f %*.*f %*.*f"
            headfmt = "%-24s %-12s  %*s %*s %*s %*s %*s %*s %*s %*s %*s"
            if self.Hcount == 1:
                print(headfmt % ('# Timestamp', 'Device',
                       tmpspace - 1, 'r/s', tmpspace, 'w/s',
                       tmpspace, 'kb_r/s', tmpspace, 'kb_w/s',
                       tmpspace, 'r_pct', tmpspace, 'w_pct',
                       tmpspace, 'o_pct', tmpspace, 'Rs/s',
                       tmpspace, 'o_cnt'))
        else:
            valfmt = "%-12s %*.*f %*.*f %*d %*d %*.*f %*.*f %*.*f %*.*f %*.*f"
            headfmt = "%-12s %*s %*s %*s %*s %*s %*s %*s %*s %*s"
            if self.Hcount == 1:
                print(headfmt % ('# Device',
                   tmpspace, 'r/s', tmpspace, 'w/s',
                   tmpspace, 'kb_r/s', tmpspace, 'kb_w/s',
                   tmpspace, 'r_pct', tmpspace, 'w_pct',
                   tmpspace, 'o_pct', tmpspace, 'Rs/s',
                   tmpspace, 'o_cnt'))

        if p_r == {} or p_w == {} or p_rkb == {} or p_wkb == {} or \
            p_rpw == {} or p_wpw == {} or p_opw == {} or \
            p_resid == {} or p_other == {}:
            # no values for some metric (e.g. near start of archive)
            if "t" in TapestatOptions.xflag:
                headfmt = "%-24s %-12s  %*s %*s %*s %*s %*s %*s %*s %*s %*s"
                print(headfmt % (timestamp, 'NODATA',
                    rrqmspace - 1, '?', wrqmspace, '?',
                    precision + 5, '?', precision + 5, '?',
                    precision + 5, '?', precision + 5, '?',
                    headfmtavgspace - 1, '?', headfmtquspace - 1, '?',
                    precision + 5, '?'))
            return

        try:
            if TapestatOptions.Gflag:
                aggr_r = aggr_w = aggr_rkb = aggr_wkb = aggr_actual_rpw = aggr_actual_wpw =  0.0
                aggr_actual_opw = aggr_resid_cnt = aggr_o_cnt = 0.0
                aggr_count = 0

            for inst in sorted(instlist):
                # basic stats
                r = (c_r[inst] - p_r[inst]) / dt
                w = (c_w[inst] - p_w[inst]) / dt
                rkb = (c_rkb[inst] - p_rkb[inst]) / dt / 1000.0 # bytes to kb
                wkb = (c_wkb[inst] - p_wkb[inst]) / dt / 1000.0

                #calculate and convert from nano seconds
                rpw = 100 * (c_rpw[inst] - p_rpw[inst])/ 10.0**9 / dt
                wpw = 100 * (c_wpw[inst] - p_wpw[inst]) / 10.0**9 / dt

                actual_rpw = rpw
                actual_wpw = wpw

                opw = 100 * (c_opw[inst] - p_opw[inst]) / 10.0**9 / dt
                actual_opw = opw

                resid_cnt = (c_resid[inst] - p_resid[inst]) / dt / 1000.0

                #The  number of I/Os, expressed as the number per second averaged
                #over the interval, that were included as "other" is o_cnt
                o_cnt = (c_other[inst] - p_other[inst]) / dt / 1000.0


                device = inst   # prepare name for printing
                badcounters = (r < 0 or w < 0 or rkb < 0 or wkb < 0 or rpw < 0 or
                               wpw < 0 or opw < 0 or resid_cnt < 0 or o_cnt < 0)

                if "t" in TapestatOptions.xflag:
                    if badcounters:
                        print(headfmt % (timestamp, device, rrqmspace,
                                         '?', wrqmspace, '?', precision + 5,
                                         '?', precision + 4, '?', precision + 6,
                                         '?', precision + 6, '?', headfmtavgspace,
                                         '?', headfmtquspace, '?', precision+5, '?'))
                    else:
                        if TapestatOptions.Rflag and re.search(regex,device) is None:
                            continue

                        if TapestatOptions.Gflag:
                            aggr_count += 1

                        if "noidle" in TapestatOptions.xflag:
                            if rkb == 0 and wkb == 0 and r == 0 and w == 0 :
                                continue

                        if not TapestatOptions.Gflag:
                            print(valfmt % (timestamp, device, tmpspace,
                                            precision, r, tmpspace,
                                            precision, w, tmpspace,
                                            rkb, tmpspace, wkb, tmpspace,
                                            precision, actual_rpw, tmpspace,
                                            precision, actual_wpw, tmpspace,
                                            precision, actual_opw, tmpspace,
                                            precision, resid_cnt, tmpspace,
                                            precision, o_cnt))
                else:
                    if badcounters:
                        print(headfmt % (device, rrqmspace, '?', wrqmspace, '?',
                                         precision + 5, '?', precision + 4, '?',
                                         precision + 6, '?', precision + 6, '?',
                                         headfmtavgspace, '?', headfmtquspace,
                                         '?', precision + 5, '?', awaitspace,
                                         '?', awaitspace, '?', utilspace, '?'))
                    else:
                        if TapestatOptions.Rflag and re.search(regex,device) is None:
                            continue

                        if TapestatOptions.Gflag:
                            aggr_count += 1

                        if "noidle" in TapestatOptions.xflag:
                            if rkb == 0 and wkb == 0 and r == 0 and w == 0 :
                                continue

                        if not TapestatOptions.Gflag:
                            print(valfmt % (device, tmpspace, precision, r,
                                            tmpspace, precision, w, tmpspace,
                                            rkb, tmpspace, wkb, tmpspace,
                                            precision, actual_rpw, tmpspace,
                                            precision, actual_wpw, tmpspace,
                                            precision, actual_opw, tmpspace,
                                            precision, resid_cnt, tmpspace,
                                            precision, o_cnt))

                if TapestatOptions.Gflag and not badcounters:
                    aggr_r = aggregate(aggr, aggr_r, r)
                    aggr_w = aggregate(aggr, aggr_w, w)
                    aggr_rkb = aggregate(aggr, aggr_rkb, rkb)
                    aggr_wkb = aggregate(aggr, aggr_wkb, wkb)
                    aggr_actual_rpw = aggregate(aggr, aggr_actual_rpw, actual_rpw)
                    aggr_actual_wpw = aggregate(aggr, aggr_actual_wpw, actual_wpw)
                    aggr_actual_opw = aggregate(aggr, aggr_actual_opw, actual_opw)
                    aggr_resid_cnt = aggregate(aggr, aggr_resid_cnt, resid_cnt)
                    aggr_o_cnt = aggregate(aggr, aggr_o_cnt, o_cnt)
            # end of loop

            if TapestatOptions.Gflag:
                if TapestatOptions.Gflag == 'avg' and aggr_count > 0:
                    aggr_r /= aggr_count
                    aggr_w /= aggr_count
                    aggr_rkb /= aggr_count
                    aggr_wkb /= aggr_count
                    aggr_actual_rpw /= aggr_count
                    aggr_actual_wpw /= aggr_count
                    aggr_actual_opw /= aggr_count
                    aggr_resid_cnt /= aggr_count
                    aggr_o_cnt /= aggr_count


                # report aggregate values - the 'device' here is reported as the regex used for the aggregation
                device = '%s(%s)' % (aggr, regex)
                if "t" in TapestatOptions.xflag:
                    print(valfmt % (timestamp, device, tmpspace, precision,
                                    aggr_r, tmpspace, precision, aggr_w,
                                    tmpspace, aggr_rkb, tmpspace, aggr_wkb,
                                    tmpspace, precision, aggr_actual_rpw,
                                    tmpspace, precision, aggr_actual_wpw,
                                    tmpspace, precision, aggr_actual_opw,
                                    tmpspace, precision, aggr_resid_cnt,
                                    tmpspace, precision, aggr_o_cnt))
                else:
                    print(valfmt % (device, tmpspace, precision, aggr_r,
                                    tmpspace, precision, aggr_w, tmpspace,
                                    aggr_rkb, tmpspace, aggr_wkb, tmpspace,
                                    precision, aggr_actual_rpw, tmpspace,
                                    precision, aggr_actual_wpw, tmpspace,
                                    precision, aggr_actual_opw, tmpspace,
                                    precision, aggr_resid_cnt, tmpspace,
                                    precision, aggr_o_cnt))

        except KeyError:
            # instance missing from previous sample
            pass

class TapestatOptions(pmapi.pmOptions):
    # class attributes
    xflag = []
    uflag = None
    Pflag = 2
    Rflag = ""
    Gflag = ""
    def checkOptions(self, manager):
        if TapestatOptions.uflag:
            if manager._options.pmGetOptionInterval():
                print("Error: -t incompatible with -u")
                return False
            if manager.type != PM_CONTEXT_ARCHIVE:
                print("Error: -u can only be specified with -a archive")
                return False
        return True

    def extraOptions(self, opt, optarg, index):
        if opt == "x":
            TapestatOptions.xflag += optarg.replace(',', ' ').split(' ')
        elif opt == "u":
            TapestatOptions.uflag = True
        elif opt == "P":
            TapestatOptions.Pflag = int(optarg)
        elif opt == "R":
            TapestatOptions.Rflag = optarg
        elif opt == "G":
            TapestatOptions.Gflag = optarg

#   all this stuff needs changes but leaving it as it is for now, anyway we will first get
#   it working without any arguments

    def __init__(self):
        pmapi.pmOptions.__init__(self, "A:a:D:G:h:O:P:R:S:s:T:t:uVZ:z?x:")
        self.pmSetOptionCallback(self.extraOptions)
        self.pmSetLongOptionHeader("General options")
        self.pmSetLongOptionAlign()
        self.pmSetLongOptionArchive()
        self.pmSetLongOptionDebug()
        self.pmSetLongOption("aggregate", 1, "G", "method",
                             "aggregate values for devices matching -R regex" +
                             " using 'method' (sum, avg, min or max)")
        self.pmSetLongOptionHost()
        self.pmSetLongOptionOrigin()
        self.pmSetLongOption("precision", 1, "P", "N", "N digits after the decimal separator")
        self.pmSetLongOption("regex", 1, "R", "pattern",
                             "only report for devices names matching pattern,"
                             " e.g. 'sd[a-zA-Z]+'. See also -G.")
        self.pmSetLongOptionStart()
        self.pmSetLongOptionSamples()
        self.pmSetLongOptionFinish()
        self.pmSetLongOptionInterval()
        self.pmSetLongOption("no-interpolation", 0, "u", "", "disable interpolation mode with archives")
        self.pmSetLongOptionVersion()
        self.pmSetLongOptionTimeZone()
        self.pmSetLongOptionHostZone()
        self.pmSetLongOptionHelp()
        self.pmSetLongOptionHeader("Extended options")
        self.pmSetLongOption("", 1, 'x', "LIST", "comma separated extended options: [[t],[h],[noidle]]")
        self.pmSetLongOptionText("\t\tt\tprecede every line with a timestamp in ctime format")
        self.pmSetLongOptionText("\t\th\tsuppress headings")
        self.pmSetLongOptionText("\t\tnoidle\tdo not display idle devices")

if __name__ == '__main__':
    try:
        opts = TapestatOptions()
        manager = pmcc.MetricGroupManager.builder(opts, sys.argv)
        if not opts.checkOptions(manager):
            raise pmapi.pmUsageErr

        if TapestatOptions.uflag:
            # -u turns off interpolation
            manager.pmSetMode(PM_MODE_FORW, manager._options.pmGetOptionOrigin(), None)
        missing = manager.checkMissingMetrics(TAPESTAT_METRICS)
        if missing is not None:
            sys.stderr.write('Error: not all required metrics are available\nMissing: %s\n' % (missing))
            sys.exit(1)
        manager["tapestat"] = TAPESTAT_METRICS
        #print "calling TapestatReport()"
        manager.printer = TapestatReport()
        sts = manager.run()
        sys.exit(sts)
    except pmapi.pmErr as error:
        sys.stderr.write('%s: %s\n' % (error.progname(), error.message()))
    except pmapi.pmUsageErr as usage:
        usage.message()
        sys.exit(1)
    except KeyboardInterrupt:
        pass
